Araliphatic sulfonium and their use

ABSTRACT

Sulfonium salts of the formulae I to IV ##STR1## in which A is C 1  -C 12  alkyl, C 3  -C 8  cycloalkyl, C 4  -C 10  cycloalkylalkyl, phenyl which is unsubstituted or mono- or polysubstituted by C 1  -C 8  alkyl, C 1  -C 4  alkoxy, halogen, nitro, phenyl, phenoxy, alkoxycarbonyl having 1-4 C atoms in the alkoxy radical or acyl having 1-12 C atoms, Ar, Ar 1  and Ar 2 , independently of one another, are each unsubstituted or mono- or polysubstituted phenyl, or naphthyl which is unsubstituted or mono- or polysubstituted each arylene is an unsubstituted or mono- or polysubstituted phenylene or unsubstituted or mono- or polysubstituted naphthylene and Q.sup.⊖ is SbF 6   - , AsF 6   -  or SbF 5  OH -  are valuable curing agents and curing accelerators in the heat-curing of cationically polymerizable compounds, preferably epoxy resins.

This is a divisional of application Ser. No. 462,252 filed on Jan. 9,1990, now U.S. Pat. No. 5,013,814.

The present invention relates to novel araliphatic sulfonium salts,their use in curable mixtures containing cationically polymerizablecompounds and to the products obtained from these mixtures byheat-curing.

It is known to use sulfonium salts as curing agents or curingaccelerators in the heat-curing of cationically polymerizable organiccompounds. The curing agents known from the Journal of CoatingsTechnology, Vol. 53, No. 675, April 1981, pages 43-51, such asα-phenethyl-substituted sulfonium tetrafluoroborates, are slowlydecomposed upon storage, so that the curable mixtures prepared usingthese sulfonium salts have only a relatively short pot life.

The epoxide formulations which are described in Journal of AppliedPolymer Science, Vol. 32, 5727-5732 (1986) and containmonobenzylsulfonium salts are distinguished by a long pot life, althoughrelatively long and thus uneconomical curing times are required tocompletely cure them.

It has now been found that certain araliphatic sulfonium salts whenmixed with cationically polymerizable organic compounds have a distinctlatency at room temperature, thus allowing a wide processing margin, andthat rapid curing takes place upon heating the mixtures according to theinvention to more than 100° C.

The invention relates to sulfonium salts of the formulae I to IV##STR2## in which A is C₁ -C₁₂ alkyl, C₃ -C₈ cycloalkyl, C₄ -C₁₀cycloalkylalkyl, phenyl which is unsubstituted or mono- orpolysubstituted by C₁ -C₈ alkyl, C₁ -C₄ alkoxy, halogen, nitro, phenyl,phenoxy, alkoxycarbonyl having 1-4 C atoms in the alkoxy radical or acylhaving 1-12 C atoms, Ar, Ar¹ and Ar², independently of one another, areeach phenyl which is unsubstituted or mono- or polysubstituted by C₁ -C₈alkyl, C₁ -C₄ alkoxy, halogen, nitro, phenyl, phenoxy, alkoxycarbonylhaving 1-4 C atoms in the alkoxy radical or acyl having 1-12 C atoms oris naphthyl which is unsubstituted or mono-or polysubstituted by C₁ -C₈alkyl, C₁ -C₄ alkoxy, halogen, nitro, phenyl, phenoxy, alkoxycarbonylhaving 1-4 C atoms in the alkoxy radical or acyl having 1-12 C atoms,each arylene is phenylene which is unsubstituted or mono- orpolysubstituted by C₁ -C₈ alkyl, C₁ -C₄ alkoxy, halogen, nitro, phenyl,phenoxy, alkoxycarbonyl having 1-4 C atoms in the alkoxy radical or acylhaving 1-12 C atoms or naphthylene which is unsubstituted or mono- orpolysubstituted by C₁ -C₈ alkyl, C₁ -C₄ alkoxy, halogen, nitro, phenyl,phenoxy, alkoxycarbonyl having 1-4 C atoms in the alkoxy radical or acylhaving 1-12 C atoms and Q.sup.⊖ is SbF₆ ⁻, AsF₆ ⁻ or SbF₅ OH⁻.

Preferably, the invention relates to sulfonium salts of the formulae Iand II ##STR3## in which A is C₁ -C₁₂ alkyl, C₃ -C₈ cycloalkyl, C₄ -C₁₀cycloalkylalkyl, phenyl which is unsubstituted or mono- orpolysubstituted by C₁ -C₈ alkyl, C₁ -C₄ alkoxy, halogen, nitro, phenyl,phenoxy, alkoxycarbonyl having 1-4 C atoms in the alkoxy radical or acylhaving 1-12 C atoms, Ar, Ar¹ and Ar², independently of one another, areeach phenyl which is unsubstituted or mono- or polysubstituted by C₁ -C₈alkyl, C₁ -C₄ alkoxy, halogen, nitro, phenyl, phenoxy, alkoxycarbonylhaving 1-4 C atoms in the alkoxy radical or acyl having 1-12 C atoms, oris naphthyl which is unsubstituted or mono- or polysubstituted by C₁ -C₈alkyl, C₁ -C₄ alkoxy, halogen, nitro, phenyl, phenoxy, alkoxycarbonylhaving 1-4 C atoms in the alkoxy radical or acyl having 1-12 C atoms,and Q.sup.⊖ is SbF₆ ⁻, AsF₆ ⁻ or SbF₅ OH⁻.

Preferably, A is C₁ -C₁₂ alkyl or phenyl which is unsubstituted orsubstituted by halogen or C₁ -C₄ alkyl, Ar, Ar¹ and Ar², independentlyof one another, are each phenyl which is unsubstituted or mono- orpolysubstituted by C₁ -C₈ alkyl, C₁ -C₄ alkoxy, Cl or Br, and Q.sup.⊖ isSbF₆ ⁻ or SbF₅ OH⁻, for example dibenzylethylsulfoniumhexafluoroantimonate.

Particularly preferred sulfonium salts are those of the formula II inwhich Ar, Ar¹ and Ar², independently of one another, are each phenylwhich is unsubstituted or substituted by C₁ -C₈ alkyl, C₁ -C₄ alkoxy, Clor Br and Q.sup.⊖ is SbF₆ ⁻ or SbF₅ OH⁻, such as in particulartribenzylsulfonium hexafluoroantimonate.

C₁ -C₁₂ alkyl as A in formula I can be straight-chain or branched. Forexample, A can be methyl, ethyl, isopropyl, n-butyl, sec-butyl,tert-butyl, n-octyl or n-dodecyl.

Examples of suitable cycloalkyls are cyclopropyl, cyclopentyl,cyclohexyl, and cyclooctyl.

Examples of suitable cycloalkylalkyls are cyclohexylmethyl andcyclohexylethyl.

A substituted phenyl or naphthyl as A, Ar, Ar¹ and Ar² can beidentically or differently substituted phenyl or naphthyl. Examples arep-tolyl, xylyl, ethylphenyl, methoxyphenyl, ethoxyphenyl,p-chlorophenyl, 2,4-, 3,4- or 2,6-dichlorophenyl, bromophenyl,acetylphenyl, trimethylphenyl, methylnaphthyl, methoxynaphthyl,ethoxynaphthyl, chloronaphthyl, bromonaphthyl and biphenyl.

A substituted phenylene or naphthylene as arylene can be, for examplemethylphenylene, ethylphenylene, methoxyphenylene, ethoxyphenylene,chlorophenylene, dichlorophenylene, bromophenylene, acetylphenylene,trimethylphenylene, methylnaphthylene, methoxynaphthylene,ethoxynaphthylene, chloronaphthylene or bromonaphthylene. Preferably,arylene is an unsubstituted phenylene or naphthylene.

The sulfonium salts according to the invention of the formulae I and IIcan be prepared by one of the processes disclosed in Houben-Weyl,Methoden der organischen Chemie (Methods of Organic Chemistry), VolumeIX, pages 171 ff (1955), and supplement E 11, pages 405 ff (1985), byreacting, for example, a sulfide of the formula V

    Ar--CH.sub.2 --S--CH.sub.2 --Ar.sup.1                      (V),

in which Ar and Ar¹ are as defined in formula I or II either

(a) with molar amounts of an oxonium salt of the formula VI ##STR4## inwhich A is as defined in formula I and Z⁻ is Q⁻, SbCl₆ ⁻, BF₄ ⁻ or PF₆ ⁻to give compounds of the formula I or the formula Ia ##STR5## in whichZa⁻ is SbCl₆ ⁻, BF₄ ⁻ or PF₆ ⁻ and subsequently reacting the compoundsof the formula Ia by anion exchange with an alkali metal salt or aquaternary ammonium salt of the formula VII

    Y.sup.+ Q.sup.-                                            (VII)

in which Y⁺ is an alkali metal cation or N(R₄)⁺ in which R is hydrogenof C₁ -C₄ alkyl and Q⁻ is as defined in formula I to give a compound ofthe formula I, or

(b) in the presence of a strong acid with at least a molar amount of analcohol of the formula VIII

    Ar.sup.2 --CH.sub.2 --OH                                   (VIII),

in which Ar² is as defined in formula II, to give a sulfonium salt ofthis acid of the formula IIa ##STR6## and subsequently reacting thesulfonium salt of the formula IIa with an alkali metal salt or aquaternary ammonium salt of the formula VII to give a compound of theformula II.

Analogously, the compounds according to the invention of the formulaeIII and IV can be prepared by reacting, for example, 1 mol of a compoundof the formula IX

    Ar--CH.sub.2 --S--CH.sub.2 --arylene--CH.sub.2 --S--CH.sub.2 --Ar.sup.1(IX)

in which Ar and Ar¹ are as defined in formula III or IV either

(c) with 2 mol of an oxonium salt of the formula VI to give compounds ofthe formula III or the formula IIIa ##STR7## in which Za⁻ is SbCl₆ ⁻,BF₄ ⁻ or PF₆ ⁻ and subsequently reacting the compound of the formulaIIIa by anion exchange with an alkali metal salt or a quaternaryammonium salt of the formula VII to give a compound of the formula III,or

(d) in the presence of a strong acid with 2 mol of an alcohol of theformula VIII to give a disulfonium salt of this acid of the formula IVa##STR8## and subsequently reacting the disulfonium salt of the formulaIVa with an alkali metal salt or a quaternary ammonium salt of theformula VII to give a compound of the formula IV.

The compounds of the formulae V, VI, VII, VIII and IX are knowncompounds, some of which are commercially available.

For example, sulfides of the formula V are described in Houben-Weyl,Volume 9, page 93 (1955), or Volume E 11, page 158 (1985) or arecommercially available from Fluka and Aldrich Co.

Oxonium salts of the formula VI are known, for example, fromHouben-Weyl, Volume 6/3, page 328 (1965), or from U.S. Pat. No.3,585,227.

Alkali metal salts or quaternary ammonium salts of the formula VII, forexample NaSbF₆, NaAsF₆ or NH₄ AsF₆ are commercially available, forexample from Morton Thiokol Co. Likewise, alcohols of the formula VIII,for example benzyl alcohol or chlorinated benzyl alcohols, arecommercially available.

Compounds of the formula IX can be prepared in a known manner byreacting, for example, 1 mol of an unsubstituted or substitutedα,α'-dihalogenomethylarylene of the formula X

    Hal--CH.sub.2 --arylene--CH.sub.2 --Hal                    (X)

in the presence of alkali metal hydroxide solution with 2 mol of anunsubstituted or substituted mercaptan of the formula XI

    Ar--CH.sub.2 SH or Ar.sup.1 --CH.sub.2 --SH                (XI)

to give compounds of the formula IX.

Compounds of the formula I or III in which A is the radical of theformula XII ##STR9## in which R' and R", independently of one another,are each a hydrogen atom or together with the ethylene radical alkylcontaining up to 12 C atoms or cycloalkyl containing up to 8 C atoms canalso be prepared by reacting a sulfide of the formula V in the presenceof a strong acid with at least a molar amount of an olefin of theformula XIII

    R'--CH═CH--R"                                          (XIII)

to give a sulfonium salt of the formula XIV or XV ##STR10## andsubsequently reacting the sulfonium salt of the formula XIV or XV withan alkali metal salt or a quaternary ammonium salt of the formula VII togive a compound of the formula I or III in which A is the radical of theformula XII.

The olefins of the formula XIII used are, for example, ethylene,propylene, 1-butene, 2-butene, isobutylene, 1-pentene, 2-pentene,cyclobutene, cyclopentene or cyclohexene and the strong acids used are,for example, H₂ SO₄, HPF₆, HBF₄, HClO₄ or CF₃ SO₃ H.

As mentioned at the beginning, the compounds according to the inventionof the formulae I, II, III and IV are valuable curing agents and curingcatalysts for the heat-curing of cationically polymerizable compounds.

The invention accordingly also relates to a curable mixture containing(a) at least one sulfonium salt of the formula I, II, III or IV and (b)at least one cationically polymerizable organic material.

Preferably, the mixtures according to the invention contain at least onesulfonium salt of the formula I or II.

Cationically polymerizable organic materials which are suitable for thecurable mixtures according to the invention are, for example, of thetypes below, it being possible for these materials to be used bythemselves or as mixtures of at least two components:

I. Ethylenically unsaturated compounds polymerizable by a cationicmechanism. These include

1. Monoolefins and diolefins, for example isobutylene, butadiene,isoprene, styrene, α-methylstyrene, divinylbenzenes, N-vinylpyrrolidone,N-vinylcarbazole and acrolein.

2. Vinyl ethers, for example methyl vinyl ether, isobutyl vinyl ether,trimethylolpropane trivinyl ether, ethylene glycol divinyl ether; cyclicvinyl ethers, for example 3,4-dihydro-2-formyl-(2H)-pyran (dimericacrolein) and the 2-hydroxymethyl-3,4-dihydro-(2H)-pyran ester of3,4-dihydro-(2H)-pyran-2-carboxylic acid.

3. Vinyl esters, for example vinyl acetate and vinyl stearate.

II. Cationically polymerizable heterocyclic compounds, for exampleethylene oxide, propylene oxide, epichlorohydrin, glycidyl ethers ofmonohydric alcohols or phenols, for example n-butyl glycidyl ether,n-octyl glycidyl ether, phenyl glycidyl ether and cresyl glycidyl ether;glycidyl acrylate, glycidyl methacrylate, styrene oxide and cyclohexeneoxide; oxetanes such as 3,3-dimethyloxetane and3,3-di(chloromethyl)oxetane; tetrahydrofuran; dioxolanes, trioxane and1,3,6-trioxacyclooctane; lactones such as β-propiolactone,γ-valerolactone and ε-caprolactone; thiiranes such as ethylene sulfideand propylene sulfide; epoxy resins; linear and branched polymers havingglycidyl groups in the side chains, for example homopolymers andcopolymers of polyacrylate and polymethacrylate glycidyl esters.

Of the abovementioned polymerizable compounds, of particular importanceare the epoxy resins and in particular the diepoxides and polyepoxidesand epoxy resin prepolymers of the type used for preparing crosslinkedepoxy resins. The diepoxides and polyepoxides can be aliphatic,cycloaliphatic or aromatic compounds. Examples of these compounds arethe glycidyl ethers and β-methyl glycidyl ethers of aliphatic andcycloaliphatic diols or polyols, for example those of ethylene glycol,1,2-propanediol, 1,3-propanediol, 1,4-butanediol, diethylene glycol,polyethylene glycol, polypropylene glycol, glycerol, trimethylolpropaneor 1,4-dimethylolcyclohexane or 2,2-bis(4-hydroxycyclohexyl)propane, theglycidyl ethers of diphenols and polyphenols, for example resorcinol,4,4'-dihydroxydiphenylmethane, 2,2-(4,4'-dihydroxydiphenyl)propanenovolaks and 1,1,2,2-tetrakis(4-hydroxyphenyl)ethane. Further examplesare N-glycidyl compounds, for example the diglycidyl compounds ofethyleneurea, 1,3-propyleneurea or 5,5-dimethylhydantoin or4,4'-methylenebis(5,5'-dimethylhydantoin), or those such as triglycidylisocyanurate.

Further glycidyl compounds of industrial importance are the glycidylesters of carboxylic acids, in particular di- and polycarboxylic acids.Examples of these are the glycidyl esters of succinic acid, adipic acid,azelaic acid, sebacic acid, phthalic acid, terephthalic acid, tetra- andhexahydrophthalic acid, isophthalic acid or trimellitic acid, or ofdimerized fatty acids.

Examples of polyepoxides which are different from glycidyl compounds arethe diepoxides of vinylcyclohexene and dicyclopentadiene,3-(3',4'-epoxycyclohexyl)-8,9-epoxy-2,4-dioxaspiro[5.5]undecane,3',4'-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate, butadienediepoxide or isoprene diepoxide, epoxidized linolic acid derivatives orepoxidized polybutadiene.

Preferred epoxy resins are diglycidyl ethers, which can beprelengthened, of dihydric phenols or dihydric aliphatic alcohols having2 to 4 carbon atoms. Particular preference is given to the diglycidylethers, which can be prelengthened, of 2,2-bis(4-hydroxyphenyl)propaneand bis(4-hydroxyphenyl)methane.

Other suitable cationically polymerizable compounds are phenolic resins.

Preferred phenolic resins are resols prepared from a phenol and analdehyde. Suitable phenols include phenol itself, resorcinol,2,2-bis(p-hydroxyphenyl)propane, p-chlorophenol, phenol substituted byone or two alkyl groups each having 1 to 9 carbon atoms, such as o-, m-and p-cresol, xylenols, p-tert-butylphenol and p-nonylphenol and alsophenyl-substituted phenols, in particular p-phenylphenol. The aldehydewhich is condensed with the phenol is preferably formaldehyde, but otheraldehydes such as acid aldehyde and furfural are also suitable. Ifdesired, a mixture of these curable phenol/aldehyde resins can be used.

The preferred resols are condensation products of phenol,p-chlorophenol, resorcinol or o-, m- or p-cresol with formaldehyde.

The curable mixtures according to the invention can be obtained in anydesired form, for example as homogeneous liquid mixtures or inhomogeneous or non-homogeneous glassy form. Homogeneous glassy productscan be obtained in a manner known per se, for example by liquefyingsolid polymerizable organic materials, if appropriate with the additionof suitable solvents, heating to temperatures above their glasstransition temperature, addition of the curing agent according toformula I or II and cooling of the resulting mixture.

In the curable mixtures according to the invention, the amount ofcomponent (a) is in general 0.05 to 5% by weight, relative to the amountof (b).

If desired, further heat-curing agents (c), for example polycarboxylicacids, polycarboxylic anhydrides or polyphenols, can be present in thecurable mixtures according to the invention, especially in the presenceof an epoxy resin as cationically polymerizable compound. However, thesecuring agents must be free of functional groups which interfere in orinhibit the cationic curing by sulfonium salts, for example amino,nitrilo or phosphino groups. The relative amount of such a curing agentis less than the stoichiometric amount of the further curing agentnecessary for the complete curing of (b).

In addition, the curable mixtures according to the invention can containstill further compounds copolymerizable with component (b), for examplecyclic ethers or cyclic lactones, as reactive solvents. These reactivesolvents are, for example, propylene carbonate, ε-caprolactone,γ-butyrolactone or tetrahydrofurfuryl alcohol. These copolymerizablecompounds must also be free of groups which interfere in or inhibit thecationic curing. In the case where copolymerizable compounds are used,their relative amount is in general between 1 and 50% by weight,relative to the amount of component (b), and the amount of component (a)is in general 0.05 to 5% by weight, relative to the amount of component(b) and the amount of the copolymerizable compound.

The curable mixtures according to the invention can also contain furtherknown additives customarily used in the technology of polymerizablematerials. Examples of these additives are pigments, dyes, fillers andreinforcing agents, glass fibers and other fibres, flame retardants,antistatics, flow-improving agents, antioxidants and light stabilizers.

The mixtures according to the invention have an unusually long pot lifeat room temperature, which is of particular advantage when they areprocessed in complicated applications.

Quite generally, the curable mixtures according to the invention can beused for the preparation of cured products and can be used in theformulation adapted to the particular specific field of application, forexample in the form of coating materials, lacquers, moulding compounds,dip-coating resins, casting resins, impregnating resins, laminatingresins, 1- or 2-component adhesives or matrix resins.

The mixtures according to the invention can be rapidly cured atrelatively low temperatures. In general, temperatures in the range from20° to 200° C., preferably from 60° to 180° C., in particular 80° to150° C., are used for the curing. The mixtures according to theinvention can also first be pre-cured at lower temperatures until thecurable composition becomes a gel which is then followed by curing atelevated temperatures.

The products obtained from the mixtures according to the invention byheat-curing are distinguished in particular by a high T_(G) value andhigh temperature resistance. Furthermore, the invention accordingly alsorelates to the product obtained by heat-curing of the mixtures accordingto the invention, which are solid, insoluble and unmeltable productswhich are crosslinked in three dimensions.

The curing is usually carried out in combination with moulding to givemoulded, impregnated, coated or bonded products.

EXAMPLE 1

A mixture of 1.07 g (5 mmol) of dibenzyl sulfide and 1.70 (5 mmol) oftriethyloxonium hexafluoroantimonate in 20 ml of methylene chloride isstirred under nitrogen at room temperature (RT) for 21/2 hours (h). Thecolourless solution is extracted with water, and the organic phase isdried over magnesium sulfate. The solvent is removed on a rotaryevaporator, the crystalline residue is washed with a small amount oftoluene and dried in vacuo at room temperature.

This gives 2.20 g (92% of theory) of dibenzylethylsulfoniumhexafluoroantimonate in the form of colourless crystals of melting point119°-121° C.

Elemental analysis for C₁₆ H₁₉ SSbF₆ : Calculated: (%) C=40.11; %H=4.00; % S=6.69. Found: (%) C=39.91; % H=4.03; % S=6.88.

¹ H-NMR (100 MHz, d₆ -acetone) in ppm: 1.41 (triplet, 3H); 3.50(quartet, 2H); 4.91 (singlet, 4H); 7.53 (multiplet, 10H).

EXAMPLE 2

a) 21.4 g (0.1 mol) of dibenzyl sulfide and 10.8 g (0.1 mol) of benzylalcohol in 300 ml of acetic acid are initially introduced into a 750 mlreaction vessel equipped with stirrer, thermometer and dropping funnel.

20 ml of concentrated sulfuric acid are added dropwise with stirringover a period of 5 minutes (min). The reaction mixture is then heated inan oil bath to an inside temperature of 70° C. and stirred for 2 hours.The major portion of the acetic acid is distilled off, and the residueis poured into 200 ml of water. The suspension is left at 0°-5° for 1/2hour, the crystalline residue is filtered off and dried in vacuo at R.T.36.5 g (91% of theory) of tribenzylsulfonium hydrogen sulfate remain inthe form of colourless crystals of melting point 170° C.(decomposition).

b) 16.64 g (0.041 mol) of tribenzylsulfonium hydrogen sulfate aredissolved in 750 ml of warm methanol. 16.04 g (0.062 mol) of solidsodium hexafluoroantimonate are added to the cloudy solution, which isstirred at RT for 1 hour. After adding a spatula of activated carbon,the mixture is filtered, and 750 ml of water are added to the clearfiltrate. The precipitated crystals are filtered off, dried, washed with100 ml of ether and dried again. This gives 16.41 g (74% of theory) oftribenzylsulfonium hexafluoroantimonate in the form of colourlesscrystals of melting point 170° C. (decomposition).

Elemental analysis for C₂₁ H₂₁ SSbF₆ : Calculated: (%) C=46.61; %H=3.91; % S=5.92. Found: (%) C=47.44; % H=3.99; % S=6.09.

¹ H-NMR (100 MHz, d₆ -DMSO) in ppm: 4.78 (singlet, 6H); 7.32(singlet-like peak, 15H).

EXAMPLE 3

a) 10.7 g (0.050 mol) of dibenzyl sulfide and 5.4 g (0.050 mol) ofbenzyl alcohol in 50 ml of acetic acid are initially introduced into a350 ml reaction vessel equipped with stirrer, thermometer and droppingfunnel, and the mixture is heated to 50° C. in an oil bath.

A solution of 35.4 g (0.186 mol) of p-toluenesulfonic acid monohydratein 100 ml of acetic acid is then added dropwise with stirring. Stirringat an inside temperature of 80° C. is then continued for 4 hours. Themajor portion of acetic acid is removed by distillation in a rotatoryevaporator, and 100 ml of water and 50 ml of methylene chloride areadded to the residue. The mixture is shaken, the methylene chloridephase is separated off, dried over magnesium sulfate and concentrated ina rotary evaporator. 23.6 g (99% of crude yield) of a yellowish oilremain. This oil is stirred in 130 ml of toluene, resulting incrystallization. After filtration and drying, 11.1 g (47% of theory) oftribenzylsulfonium p-toluenesulfonate remain in the form of colourlesscrystals.

Elemental analysis for C₂₈ H₂₈ S₂ O₃ : Calculated: (%) C=70.56; %H=5.92; % S=13.45. Found: (%) C=69.79; % H=6.01; % S=13.60.

¹ H-NMR (100 MHz, d₆ -DMSO) in ppm: 2.34 (singlet, 3H); 4.85 (singlet,6H); 7.30/7.70 (multiplet, 19H).

b) 9.53 g (0.020 mol) of tribenzylsulfonium p-toluenesulfonate aredissolved in a mixture of 60 ml of methanol and 40 ml of water by slightwarming. At RT, 6.84 g (0.030 mol) of solid potassium hexafluoroarsenateare added, and the suspension is stirred for 2 hours. The crystallinesolid is filtered off and dried in vacuo at RT. This gives 9.48 g (96%of theory) of tribenzylsulfonium hexafluoroarsenate in the form ofcolourless crystals.

Elemental analysis for C₂₁ H₂₁ SAsF₆ : Calculated: (%) C=51.02; %H=4.28; % S=6.49. Found: (%) C=50.94; % H=4.34; % S=6.48.

¹ H-NMR (100 MHz, d₆ -DMSO), in ppm: 4.69 (singlet, 6H); 7.33(multiplet, 15H).

EXAMPLE 4

a) A solution of 108.06 g (0.45 mol) of sodium sulfite monohydrate and6.0 g of tetrabutylammonium hydrogen sulfate (phase transfer catalyst)in 120 ml of water is added to a reaction vessel equipped with stirrer,thermometer and heated dropping funnel. 96.6 g (0.60 mol) of4-chlorobenzyl chloride which has been melted at 50° C. and maintainedat this temperature are added dropwise over a period of 50 minutes withvigorous stirring, while maintaining the inside temperature at 40°-50°C. Stirring at RT is continued for another 3 hours, the mixture isextracted with 200 ml of diethyl ether, the ether phase is washed 3times with aqueous sodium chloride solution (half-saturated), dried overmagnesium sulfate, filtered, and the ether is removed in a rotaryevaporator. The residue is suspended in 100 ml of methanol, the mixtureis filtered, and the filter residue is dried. This gives 79.7 g (94% oftheory) of solid colourless di-(4-chlorobenzyl) sulfide of melting point42°-44° C.

Elemental analysis for C₁₄ H₁₂ Cl₂ S: Calculated: (%) C=59.37; % H=4.27;% S=11.32; % Cl=25.04. Found: (%) C=59.13; % H=4.35; % S=11.44; %Cl=25.14.

¹ H-NMR (100 MHz, CDCl₃) in ppm: 3.54 (singlet, 4H); 7.2 (multiplet,8H).

b) 28.6 g of a solution of HBF₄ in ether (HBF₄ content=54% by weight)are added dropwise to a solution of 22.7 g (0.080 mol) ofdi-(4-chlorobenzyl)sulfide and 13.7 g (0.096 mol) of chlorobenzylalcohol in 64 ml of methylene chloride with stirring at such a rate thatthe inside temperature remains between 15° and 25° C. Stirring at roomtemperature is continued for another 2 hours, the mixture is dilutedwith methylene chloride, and the organic phase is washed 3 times withhalf-saturated sodium chloride solution. It is dried over magnesiumsulfate, filtered, and the solvent is distilled off on a rotaryevaporator. The solid residue is suspended in 80 ml of toluene, and thesuspension is filtered. The residue is dried, after which 33.6 g (85% oftheory) of tris(4-chlorobenzyl)sulfonium tetrafluoroborate remain in theform of colourless crystals of melting point 154°-156° C.

Elemental analysis for C₂₁ H₁₈ Cl₃ S.BF₄ : Calculated: (%) C=50.89; %H=3.66; % S=6.47; % Cl=21.46. Found: (%) C=50.98; % H=3.80; % S=6.56; %Cl=21.55.

¹ H-NMR (100 MHz, d₆ -DMSO) in ppm: 4.76 (singlet, 6H); 7.4 (singlet,12H).

c) 66.95 g (0.135 mol) of tris(4-chlorobenzyl)sulfoniumtetrafluoroborate are dissolved in a 500 ml round-bottomed flask in 300ml of methylene chloride under N₂, and the mixture is cooled to 0° to 5°C. 26.0 g (0.24 mol) of sodium hexafluoroantimonate are then added,stirring at the same temperature is continued for 4 hours, and thesuspension is then filtered.

The filtrate is freed from solvent on a rotary evaporator, and theresidue is stirred in 300 ml of water at RT for 21/4 hours, the residueis filtered off and washed twice with water. The crude product is driedat RT overnight in a high vacuum. This gives 91.8 g (115.3% of theory)as the crude product.

The crude product is dissolved in 285 ml of isopropanol at 90° C., andthe solution is cooled to 0°-5° C. The precipitated crystals arefiltered and washed with a small amount of cooled isopropanol (0°-5°C.). The residue is dried at RT overnight on a high-vacuum pump. Thisgives 74.4 g (93.5% of theory) of dry tris(4-chlorobenzyl)sulfoniumhexafluoroantimonate of melting point 132°-134° C.

Elemental analysis for C₂₁ H₁₈ Cl₃ SSbF₆ : Calculated: (%) C=39.13; %H=2.81; % S=4.97; % Cl=16.5; % F=17.68; % Sb=18.99. Found: (%) C=39.1; %H=2.9; % S=4.9; % Cl=16.5; % F=17.4; % Sb=19.6.

¹ H-NMR (100 MHz in CDCl₃) in ppm: 7.1 (quartet: 12H); 4.5 (singlet:6H).

EXAMPLE 5

a) A solution of 269.0 g (1.12 mol) of sodium sulfide hydrate and 12.0 gof tetrabutylammonium hydrogen sulfate (phase transfer catalyst) in 300ml of water is placed in a reaction vessel equipped with a stirrer andthermometer. 212.6 g (1.52 mol) of 4-methylbenzyl chloride are addeddropwise below 40° C. over a period of 30 minutes with vigorousstirring. The reaction mixture is stirred at RT for 41/2 hours and thenat 50°-60° C. for 1/2 hour. The reaction mixture is cooled to 0°-5° C.and maintained at this temperature for 1/2 hour. The reaction mixture isfiltered, and the residue is dissolved in about 2 litres of ethylacetate. The organic phase is extracted twice with deionized water(pH˜6) and dried over MgSO₄. The ethyl acetate is removed on a rotaryevaporator. The residue is dried at RT overnight in a high vacuum. Thisgives 174.8 g (95% of theory) of di(p-methylbenzyl) sulfide in the formof slightly yellowish white crystals of melting point 74°-76° C.

Elemental analysis for C₁₆ H₁₈ S: Calculated: (%) C=79.29; % H=7.49; %S=13.23. Found: (%) C=79.16; % H=7.3; % S=13.47.

¹ H-NMR (100 MHz, CDCl₃) in ppm: 2.33 (singlet, 6H); 3.56 (singlet, 4H);7.15 (singlet, 8H).

b) 85.1 g (0.351 mol) of di(p-methylbenzyl) sulfide and 51.5 g (0.421mol) of p-methylbenzyl alcohol in 250 ml of methylene chloride areinitially introduced into a reaction vessel (750 ml) equipped withstirrer and thermometer under an N₂ atmosphere. 142.7 g of anapproximately 54% by weight HBF₄ solution in diethyl ether are addeddropwise at an inside temperature of 20°-30° C. over a period of 40minutes with stirring. The reaction mixture is stirred at RT for 2hours. The reaction mixture is diluted with methylene chloride andextracted 4 times with deionized water (pH 5-6). The organic phase isdried with MgSO₄, and the methylene chloride is removed on a rotaryevaporator. The product which is not completely freed of methylenechloride is stirred in 250 ml of toluene at RT for about 1 hour and thenat 0°-5° C. for 1 hour. The precipitated crystals are filtered off withsuction and washed with a small amount of toluene. The product is driedat room temperature for 19 hours in a high vacuum. This gives 118.6 g oftris(p-methylbenzyl)sulfonium tetrafluoroborate in the form of whitecrystals of melting point 168°-170° C.

¹ H-NMR (100 MHz, d₆ -acetone) in ppm: 2.33 (singlet, 9H); 4.83(singlet, 6H); 7.25 (quartet, 12H).

c) Analogously to Example 4c), 100 g (230 mmol) oftris(p-methylbenzyl)sulfonium tetrafluoroborate are reacted with 119.0 g(460 mmol) of sodium hexafluoroantimonate. Recrystallization inisopropanol gives 117.1 g (87% of theory) oftris(p-methylbenzyl)sulfonium hexafluoroantimonate in the form of whitecrystals of melting point 88°-91° C.

Elemental analysis Calculated: (%) C=49.42; % H=4.67; % S=5.5. Found:(%) C=49.8; % H=4.6; % S=6.4.

¹ H-NMR (100 MHz, d₆ -acetone) in ppm: 2.34 (singlet, 9H); 4.85(singlet, 6H); 7.25 (quartet, 12H).

EXAMPLE 6

a) A solution of 75.0 g (0.374 mol) of benzyl phenyl sulfide, 60.73 g(0.561 mol) of benzyl alcohol and 350 ml of methylene chloride areplaced in a reaction vessel equipped with stirrer and thermometer.182.45 g (1.12 mol) of 54% by weight of HBF₄ in diethyl ether are addeddropwise at an inside temperature of 20°-30° C. over a period of 35minutes with stirring. The reaction mixture is then stirred at RT for 2hours. The reaction mixture is diluted with 300-400 ml of methylenechloride and extracted 4 times with water (pH˜6). The organic phase isthen dried over MgSO₄, and the solvent is removed on a rotaryevaporator. The remaining yellow-brown oil is stirred in 400 ml oftoluene, and the product is allowed to crystallize at 0°-5° C. for about1 hour. The suspension is filtered, and the residue is washed with asmall amount of cooled toluene (0°-5° C.). The pure product is dried atRT overnight in a high vacuum. This gives 123.8 g (87% of theory) ofdibenzylphenylsulfonium tetrafluoroborate in the form of white crystalsof melting point 110°-115° C.

¹ H-NMR (in d₆ -acetone, 100 MHz) in ppm: 5.30 (quartet, 4H); 7.22-8.02(multiplet, 15H).

b) A mixture of 123.0 g (0.325 mol) of dibenzylphenylsulfoniumtetrafluoroborate in 400 ml of methylene chloride is dissolved in a 2litre round-bottomed flask at RT under N₂ until a clear solution isobtained. 117.8 g of sodium hexafluoroantimonate are then added, and themixture is stirred at RT for 31/2 hours. The suspension is then filteredthrough silica gel, and the solvent is removed from the filtrate on arotary evaporator. The slightly reddish viscous residue is againdissolved in 250 ml of methanol and, after the addition of 250 ml ofwater, the product is allowed to crystallize at RT for 1-2 hours. Thesuspension is filtered, and the residue is washed with water. Theproduct is then dried at RT overnight in a high vacuum. This gives 163.9g (95% of theory) of dibenzylphenylsulfonium hexafluoroantimonate in theform of white crystals of melting point 105°-109° C.

Elemental analysis Calculated: (%) C=45.6; % H=3.63; % S=6.08; %Sb=23.09; % F=21.62. Found: (%) C=46.5; % H=3.7; % S=6.1; % Sb=22.4; %F=20.6.

¹ H-NMR (d₆ -acetone; 100 MHz) in ppm: 5.37 (quartet, 4H); 7.25-8.04(multiplet, 15H).

EXAMPLE 7

a) 5.66 g (20 mmol) of di(4-chlorobenzyl) sulfide, prepared according toExample 4a), are reacted with 2.6 g (24 mmol) of benzyl alcohol and 8.13g (50 mmol) of 54% by weight HBF₄ in 20 ml of methylene chloride asdescribed in Example 6a). This gives 7.44 g (80% of theory) ofdi(4-chlorobenzyl)phenylsulfonium tetrafluoroborate in the form of whitecrystals of melting point 123°-125° C.

¹ H-NMR (100 MHz, CDCl₃) in ppm: 4.71 (singlet, 6H); 7.27 (doublet,12H).

b) A mixture of 7.0 g (15.2 mmol) of di(4-chlorobenzyl)phenylsulfoniumtetrafluoroborate and 25 ml of methylene chloride is stirred in a 100 mlround-bottomed flask under N₂ until a clear solution is formed, which isthen cooled to 0°-5° C. At this temperature, 5.9 g (22.8 mmol) of sodiumhexafluoroantimonate are added, and the mixture is stirred for about 3hours. The reaction mixture is filtered, and the filtrate is freed fromthe solvent on a rotary evaporator. 50 ml of deionized water are thenadded to the residue, and the product is allowed to crystallize at 0°-5°C. for 1-2 hours. The crystals which are obtained by filtration arewashed with water and dried at RT overnight in a high vacuum. This gives8.26 g of di(4-chlorobenzyl)phenylsulfonium hexafluoroantimonate in theform of white crystals of melting point 75°-77° C.

Elemental analysis: Calculated: (%) C=41.34; % H=3.14; % S=5.26; %Cl=11.62. Found: (%) C=41.24; % H=3.15; % S=5.08; % Cl=12.37.

¹ H-NMR (100 MHz) in ppm: 5.0 (muliplet, 6H); 7.44 (multiplet, 13H).

EXAMPLE 8

a) 51.4 g (0.263 mol) of 2,4-dichlorobenzyl chloride, 47.4 g (0.197 mol)of sodium sulfide hydrate and 2.5 g of tetrabutylammonium hydrogensulfate in 60 ml of water are reacted as in Example 5a). This gives 45.9g (99% of theory) of bis(2,4-dichlorobenzyl) sulfide in the form of ayellowish clear liquid.

Elemental analysis: Calculated: (%) C=47.76; % H=2.86; % S=9.11; %Cl=40.28. Found: (%) C=47.4; % H=2.9; % S=8.3; % Cl=41.64.

¹ H-NMR (100 MHz, CDCl₃) in ppm: 3.74 (singlet, 4H); 7.12-7.41(multiplet, 6H).

b) 7.04 g (20 mmol) of bis(2,4-dichlorobenzyl) sulfide, 4.75 g (26.8mmol) of 2,4-dichlorobenzyl alcohol and 9.26 g (57 mmol) of 54% byweight HBF₄ (in diethyl ether) in 16 ml of methylene chloride arereacted as in Example 5b). This gives 3.76 g (31% of theory) oftris(2,4-dichlorobenzyl)sulfonium tetrafluoroborate in the form of whitecrystals of melting point 180°-182° C.

¹ H-NMR (100 MHz, d₆ -acetone) in ppm: 5.22 (singlet, 6H); 7.2-7.85(multiplet, 9H).

c) 3.5 g (5.8 mmol) of the product obtained according to Example 5b) arereacted with 2.99 g (11.6 mmol) of sodium hexafluoroantimonate in 35 mlof methylene chloride as in Example 7c) to give 3.99 g (91.9% of theory)of a crude product. The crude product is suspended in 10 ml ofisopropanol, and the mixture is stirred at RT for 1 hour. The suspensionis then cooled to 0°-5° C., filtered, and the residue is dried at RTovernight in a high vacuum. This gives 3.45 g (79.5% of theory) oftris(2,4-dichlorobenzyl)sulfonium tetrafluoroantimonate in the form ofwhite crystals of melting point 158°-160° C.

Elemental analysis: Calculated: (%) C=33.7; % H=2.02; % S=4.29; %Cl=28.44; % F=15.24; % Sb=16.28. Found: (%) C=33.4; % H=2.1; % S=4.1; %Cl=28.7; % F=14.7; % Sb=16.5.

¹ H-NMR (100 MHz, d₆ -acetone) in ppm: 5.3 (singlet, 6H); 7.4-7.8(multiplet, 9H)

EXAMPLE 9

a) A mixture of 129.7 g (0.54 mol) of sodium sulfide hydrate, 8.74 g oftetrabutylammonium hydrogen sulfate and 145 ml of water are stirred atroom temperature in a reaction vessel equipped with stirrer andthermometer, until a solution is obtained. 141.67 g (0.72 mol) of3,4-dichlorobenzyl chloride are added over a period of 10 minutes withvigorous stirring at such a rate that the inside temperature does notexceed 50° C. The reaction mixture is then stirred at RT for 31/2 hours.The reaction mixture is filtered, and the residue is dried in a highvacuum pump. The crude product is dissolved in 160 ml of refluxing ethylacetate and then allowed to crystallize at 0°-5° C. for 1-2 hours. Therecrystallized product is filtered off and dried at RT overnight in ahigh vacuum. This gives 98.37 g (77.6% of theory) ofbis(3,4-dichlorobenzyl) sulfide in the form of white crystals of meltingpoint 98°-99° C.

¹ H-NMR (100 MHz, CDCl₃) in ppm: 3.53 (singlet, 4H); 7.03-7.42(multiplet, 6H).

b) 14.08 g (40 mmol) of bis(3,4-dichlorobenzyl) sulfide and 10.47 g(58.8 mmol) of 3,4-dichlorobenzyl alcohol in 50 ml of methylene chlorideare initially introduced under an N₂ atmosphere into a reaction vesselequipped with stirrer and thermometer. 20.15 g (123.9 mmol) of hydrogentetrafluoroborate (54% in diethyl ether) are added dropwise to thesolution over a period of 10 minutes at an inside temperature of 20°-30°C. with stirring, and the reaction mixture is stirred at RT for 4 hours.Another 1.13 g of hydrogen tetrafluoroborate (54% in diethyl ether) areadded to the reaction mixture and stirring at RT is continued for 3hours. The reaction mixture is then filtered, and the residue is driedat RT in a high vacuum. The crude product is again stirred in 100 ml ofwater at RT, filtered, and the residue is dried at RT overnight in ahigh vacuum. This gives 18.3 g (76.41% of theory) oftris(3,4-dichlorobenzyl) sulfonium tetrafluoroborate in the form ofwhite crystals of melting point 201°-203° C.

¹ H-NMR (100 MHz, DMSO) in ppm: 4.8 (singlet, 6H); 7.32-7.64 (multiplet,9H).

c) A mixture of 7.5 g (12.71 mmol) of tris(3,4-dichlorobenzyl)sulfoniumtetrafluoroborate and 220 ml of acetone are stirred in a 3-necked flaskat about 30° C. under nitrogen, until a solution is obtained, and 4.93 g(19.06 mmol) of sodium hexafluoroantimonate are added. The reactionmixture is stirred at RT for 3 hours, 220 ml of methylene chloride arethen added, and the mixture is stirred at RT for 1 hour. The suspensionis filtered through kieselguhr, and the filtrate is freed from thesolvents on a rotary evaporator. The residue is again stirred at RT in50 ml of water, the mixture is filtered, and the solid product is driedat RT in a high vacuum. This gives 9.46 g (99.47% of theory) of whitecrystals (crude product 1).

9.46 g of crude product 1 are dissolved at RT in 75 ml of acetone. Undernitrogen, 4.2 g (16 mmol) of sodium hexafluoroantimonate are added, andthe mixture is stirred at room temperature for 3/4 hour. 100 ml ofmethylene chloride are added, the reaction mixture is filtered after 25minutes through kieselguhr, and the filtrate is freed from the solventson a rotary evaporator. The residue is stirred at RT in 50 ml of water,the mixture is filtered, and the residue is dried at RT overnight in ahigh vacuum. This gives 8.42 g of white crystals (crude product 2).

Crude product 2 is dissolved in 110 ml of methanol at 50°-60° C., and150 ml of water are added. The suspension is stirred at RT for 3 hours,cooled to 0°-5° C., filtered, and the residue is washed with a smallamount of water. The purified product is dried at RT overnight in a highvacuum. This gives 7.74 g (81% of theory) oftris(3,4-dichlorobenzyl)sulfonium hexafluoroantimonate in the form ofwhite crystals of melting point 164°-166° C.

¹ H-NMR (100 MHz, d₆ -acetone) in ppm: 5.17 (singlet, 6H); 7.44-7.67(multiplet, 9H).

EXAMPLE 10

a) A mixture of 98.8 g (0.411 mol) of sodium sulfide, 5.0 g oftetrabutylammonium hydrogen sulfate and 110 ml of water are stirred in areaction vessel equipped with a stirrer, thermometer and heatabledropping funnel, until a solution is obtained. 107.2 g of melted2,6-dichlorobenzyl chloride are added with vigorous stirring over aperiod of 25 minutes at such a rate that the inside temperature does notexceed 55° C. The reaction mixture is worked up as in Example 9a) togive 77.6 g (80% of theory) of bis(2,6-dichlorobenzyl) sulfide in theform of white crystals of melting point 128°-130° C.

Elemental analysis: Calculated: (%) C=47.76; % H=2.86; % Cl=40.28; %S=9.11. Found: (%) C=47.7; % H=2.95; % Cl=40.1; % S=8.96.

¹ H-NMR (100 MHz, CDCl₃) in ppm: 4.18 (singlet, 4H); 7.02-7.35(multiplet, 6H).

b) In a reaction vessel equipped with stirrer and thermometer, 14.1 g(40 mmol) of bis(2,6-dichlorobenzyl) sulfide and 9.5 g (53.6 mmol) of2,6-dichlorobenzyl alcohol are dissolved under a N₂ atmosphere in 72 mlof methylene chloride. 18.53 g (114 mmol) of hydrogen tetrafluoroborate(54% in diethyl ether) are added dropwise at an inside temperature of20°-30° C. over a period of 20 minutes with stirring, and the reactionmixture is stirred for 4 hours. Afterwards, another 2.26 g (13.9 mmol)of HBF₄ are added to the reaction mixture at RT, and stirring iscontinued for 1 hour. The reaction mixture is filtered, and the solventis removed on a rotary evaporator. The residue is stirred in 100 ml ofwater at RT, the mixture is filtered, and the residue is dried at RTovernight in a high vacuum. This gives 17.49 g (74.25% of theory) oftris(2,6-dichlorobenzyl)sulfonium tetrafluoroborate in the form of whitecrystals of decomposition point 185°-195° C.

c) A mixture of 15.0 g (25 mmol) of tris(2,6-dichlorobenzyl)sulfoniumtetrafluoroborate in 250 ml of methylene chloride is stirred in a3-necked flask at about 30° C., until a solution is obtained, and thenreacted with sodium hexafluoroantimonate at RT as in Example 9c). Workupof the reaction mixture according to Example 9c) gives 12.6 g (67.4% oftheory) of tris(2,6-dichlorobenzyl)sulfonium hexafluoroantimonate in theform of white crystals of melting point 216°-218° C.

¹ H-NMR (100 MHz, CDCl₃) in ppm: 5.61 (singlet, 6H); 7.67 (singlet, 9H).

EXAMPLE 11

In a reaction vessel equipped with stirrer and thermometer, 15.64 g(0.108 mol) of 4-chlorothiophenol, 16.10 g (0.100 mol) of 4-chlorobenzylchloride, 100 ml of toluene and 0.3 g of tetrabutylammonium hydrogensulfate are stirred at RT, until a solution is obtained. 20.0 g (0.15mol) of 30% aqueous sodium hydroxide solution are then added in portionswith thorough stirring, and the reaction mixture is stirred at RT for 3hours. It is diluted with a small amount of water, and the organic phaseis extracted 3 times with neutral water, and the organic phase is driedover MgSO₄. The solvent is removed on the rotary evaporator, the residueis stirred in 30 ml of methanol/water (9:1), the mixture is filtered,and the purified product is dried at RT for 4 hours in a high vacuum.This gives 24.1 g (89% of theory) of 4-chlorophenyl 4-chlorobenzylsulfide in the form of colourless crystals of melting point 67°-69° C.

Elemental analysis: Calculated: (%) C=58.0; % H=3.74; % S=11.91; %Cl=26.34. Found: (%) C=57.83; % H=3.8; % S=12.13; % Cl=26.21.

¹ H-NMR (100 MHz, CDCl₃) in ppm: 4.02 (singlet, 2H); 7.20 (singlet, 8H).

b) 5.2 g (19.4 mmol) of 4-chlorophenyl 4-chlorobenzyl sulfide, 4.14 g(29.0 mmol) of 4-chlorobenzyl alcohol and 14.15 g (87 mmol) of hydrogentetrafluoroborate (54% in diethyl ether) in 20 ml of methylene chlorideare reacted as in Example 6a) to give 7.23 g (77.4% of theory) of4-chlorophenylbis(4-chlorobenzyl)sulfonium tetrafluoroborate in the formof white-beige crystals of melting point 147°-148° C.

¹ H-NMR (100 MHz, d₆ -acetone) in ppm: 5.4 (quartet, 4H); 7.34-8.12(multiplet, 12H).

c) In a 3-necked flask, 6.88 g (14.3 mmol) of4-chlorophenylbis(4-chlorobenzyl)sulfonium tetrafluoroborate aredissolved under nitrogen at RT in 50 ml of methylene chloride. 5.54 g(21.4 mmol) of sodium hexafluoroantimonate are added, and the reactionmixture is stirred at RT for 31/2 hours. The suspension is filtered, andthe solvent is removed from the filtrate on a rotary evaporator. Theresidue is stirred in 50 ml of methanol, and 100 ml of water are added.The suspension is stirred at RT for 1/2 hour and at 0°-5° C. for 1/2hour, then filtered, and the residue is dried at RT overnight in a highvacuum. This gives 8.0 g (88.7% of theory) of4-chlorophenylbis(4-chlorobenzyl)sulfonium hexafluoroantimonate in theform of white crystals of melting point 130°-132° C.

¹ H-NMR (100 MHz, d₆ -acetone) in ppm: 5.45 (quartet, 4H); 7.34-8.13(multiplet, 12H).

EXAMPLE 12

a) In a reaction vessel equipped with stirrer and thermometer, 108.23(0.45 mol) of sodium sulfide hydrate and 6.0 g of tetrabutylammoniumhydrogen sulfate are dissolved at RT in 120 ml of water. 105.96 g (0.6mol) of 1-chloromethylnaphthalene are dissolved in 200 ml of toluene,and this solution is added dropwise to the initially introduced mixtureover a period of 1/2 hour at such a rate that the inside temperature is40°-50° C. After the dropwise addition, stirring of the reaction mixtureat RT is continued for 21/2 hours, and the mixture is then filtered. Theresidue is dissolved in about 500 ml of methylene chloride, and thesolution is washed 3 times with water. The organic phase is then driedwith MgSO₄, and the solvent is removed on a rotary evaporator. 250 ml ofisopropanol are then added to the residue formed. This mixture isstirred at RT and then at 0°-5° C. for 11/2 hours each time, thenfiltered, and the residue is dried at RT overnight in a high vacuum.69.9 g of the dried crude product are dissolved in 785 ml of refluxingisopropanol/acetone (1:1) and then allowed to crystallize at 0°-5° C.for 3 hours. The suspension is filtered, and the residue is washed witha small amount of isopropanol. It is then dried at RT overnight in ahigh vacuum. This gives 53.2 g (76% of theory) of bis(1-naphthylmethyl)sulfide in the form of white crystals of melting point 104°-106° C.

Elemental analysis: Calculated: (%) C=84.03; % H=5.77; % S=10.2. Found:(%) C=83.85; % H=5.8; % S=10.25.

¹ H-NMR (100 MHz, CDCl₃) in ppm: 4.13 (singlet, 4H); 7.25-8.0(multiplet, 14H).

b) 5.0 g (15.9 mmol) of bis(1-naphthylmethyl) sulfide and 5.93 g (17.5mmol) of triethyloxonium hexafluoroantimonate in 30 ml of methylenechloride are reacted according to Example 1a) to give 9.07 g (98% oftheory) of bis(1-naphthylmethyl)ethylsulfonium hexafluoroantimonate inthe form of white crystals of melting point 101°-105° C.

Elemental analysis: Calculated: (%) C=49.76; % H=4.0; % S=5.53; %Sb=21.02; % F=19.68. Found: (%) C=52.2; % H=4.2; % S=5.1; % Sb=21.3; %F=18.1.

¹ H-NMR (100 MHz, d₆ -acetone) in ppm: 1.34 (triplet, 3H); 3.77(quartet, 2H); 5.50 (quartet, 4H); 7.49-8.15 (multiplet, 14H).

EXAMPLE 13

a) 13.25 g (42.14 mol) of bis(1-naphthylmethyl) sulfide and 8.0 g (50.6mmol) of 1-hydroxymethylnaphthalene in 50 ml of methylene chloride areinitially introduced at RT under an N₂ atmosphere into a reaction vesselequipped with stirrer and thermometer. 17.2 g (105.4 mmol) of HBF₄ (54%in diethyl ether) are added dropwise over a period of 25 minutes at sucha rate that the inside temperature does not exceed 30° C. The mixture isthen stirred at RT and at 30°-35° C. for 2 hours each time. 2 g of1-hydroxymethylnaphthalene dissolved in 5 ml of methylene chloride areadded dropwise to the reaction mixture over a period of 10 minutes, andthe reaction is completed at 30°-35° C. for 11/2 hours. The reactionmixture is diluted with methylene chloride and washed 4 times with water(pH˜7). The organic phase is then dried with MgSO₄, and the solvent isremoved on a rotary evaporator. The residue is stirred at 0°-5° C. inportions with toluene until crystals can be isolated which are easy tofilter. The residue which has been filtered off is dried at RT for about20 hours in a high vacuum. This gives 21.37 g (93.5% of theory) oftris(1-naphthylmethyl)sulfonium tetrafluoroborate in the form ofwhite-greyish crystals of melting point 115°-120° C. with decomposition.

Elemental analysis: Calculated: (%) C=73.01; % H=5.02; % S=5.91. Found:(%) C=75.9; % H=5.4; % S=5.25.

b) A mixture of 15.0 g (27.7 mmol) of tris(1-naphthylmethyl)sulfoniumtetrafluoroborate in 100 ml of methylene chloride is initiallyintroduced at RT under an N₂ atmosphere into a reaction vessel equippedwith stirrer and thermometer, and 10.73 g (41.5 mmol) of sodiumhexafluoroantimonate are added. The suspension is stirred for 4 hours,then filtered, and the filtrate is evaporated to dryness. The residue isstirred at 0°-5° C. in 50 ml of methanol/water (1:1) for about 1 hour,the mixture is filtered, and the residue is stirred again at 0°-5° C. in50 ml of isopropanol for 2 hours. After filtration, the residue is driedat RT overnight in a high vacuum. This gives 10.3 g (53.8% of theory) oftris-(1-naphthylmethyl)sulfonium hexafluoroantimonate in the form ofwhite-grey crystals of decomposition point 120°-125° C.

EXAMPLE 14

a) In a reaction vessel equipped with stirrer and thermometer, 20.4 g(84.8 mmol) of sodium sulfide hydrate and 1.0 g of tetrabutylammoniumhydrogen sulfate are dissolved in 25 ml of water at RT. 25.0 g (113mmol) of 2-bromomethylnaphthalene are dissolved in 35 ml of toluene andadded dropwise over a period of 20 minutes at such a rate that theinside temperature of the reaction mixture is 40°-50° C. After thedropwise addition, the reaction mixture is stirred at RT for 21/2 hours.The reaction mixture is diluted with toluene, and the organic phase iswashed 3 times with water. The organic phase is dried with MgSO₄, andthe solvent is removed on a rotary evaporator. The crude product isdissolved in 315 ml of refluxing acetone/isopropanol (1:1), filteredwhile hot, and the solution is cooled to room temperature. The productis then allowed to crystallize at 0°-5° C. for 1/2 hour. The mixture isfiltered, and the residue is dried at RT overnight in a high vacuum.This gives 13.25 g (74.5% of theory) of bis(2-naphthylmethyl) sulfide inthe form of white crystals of melting point 119°-121° C.

Elemental analysis: Calculated: (%) C=84.03; % H=5.77; % S=10.2. Found:(%) C=84.0; % H=5.83; % S=10.47.

¹ H-NMR (100 MHz, d₆ -acetone) in ppm: 3.86 (singlet, 4H); 7.44-7.92(multiplet, 14H).

b) A mixture of 5.0 g (15.9 mmol) of bis(2-naphthylmethyl) sulfide and5.93 g (17.49 mmol) of triethyloxoniumhexafluoroantimonate in 40 ml ofmethylene chloride is stirred at RT under nitrogen for 4 hours. Thecolourless solution is diluted with methylene chloride and extractedwith water (pH˜7). The organic phase is then dried with MgSO₄ and themethylene chloride is removed on a rotary evaporator. The crude productis stirred in 40 ml of toluene at 0°-5° C. for 1 hour, the residue isfiltered and dried at RT overnight in a high vacuum. This gives 8.68 gof bis(2-naphthylmethyl)ethylsulfonium hexafluoroantimonate in the formof white crystals (94.25% of theory) of melting point 152°-153° C.

Elemental analysis: Calculated: (%) C=49.77; % H=4.0; % S=5.53. Found:(%) C=49.85; % H=4.1; % S=6.34.

¹ H-NMR (100 MHz, d₆ -acetone) in ppm: 1.50 (triplet, 3H); 3.65(quartet, 2H); 5.17 (singlet, 4H); 7.55-8.14 (multiplet, 14H).

EXAMPLE 15

a) In a reaction vessel equipped with stirrer and thermometer, 10.72 g(50 mmol) of dibenzyl sulfide are dissolved in 25 ml of methylenechloride at RT, and the solution is cooled to 0°-5° C. 12.19 g of HBF₄(54% in diethyl ether) are added dropwise over a period of 5 minutesunder an N₂ atmosphere and the introduction of propylene gas is started.The introduction of propylene gas is continued until virtually no moredibenzyl sulfide can be detected in the reaction mixture (detectionmethod: thin layer: silica gel F60; mobile phase: methylenechloride/methanol (95:5)). The reaction mixture is diluted withmethylene chloride and washed 3 times with water (pH˜7). The organicphase is dried over MgSO₄, the solvent is removed on a rotaryevaporator, and the residue is stirred in 50 ml of toluene at 0°-5° C.for about 2 hours. Afterwards, the suspension is filtered, and theresidue is dried at RT overnight in a high vacuum. This gives 9 g (52.3%of theory) of dibenzylisopropylsulfonium tetrafluoroborate in the formof white crystals of melting point 67°-69° C.

Elemental analysis: Calculated: (%) C=59.32; % H=6.15; % S=9.31. Found:(%) C=59.5; % H=6.2; % S=9.3.

b) A mixture of 3.44 g (10 mmol) of dibenzyliospropylsulfoniumtetrafluoroborate in 15 ml of methylene chloride is initially introducedinto a 3-necked flask under nitrogen at RT and cooled to 0°-5° C. Afterthe addition of 3.88 g (15 mmol) of sodium hexafluoroantimonate, thereaction mixture is stirred at 0°-5° C. for 2-3 hours. The suspension isfiltered, and the methylene chloride is removed from the filtrate on arotary evaporator. The residue is again stirred in 20 ml of water for 1hour, the mixture is filtered, and the residue is dried at RT overnightin a high vacuum. This gives 4.33 g (88% of theory) ofdibenzylisopropylsulfonium hexafluoroantimonate in the form of whitecrystals of melting point 103°-106° C.

Elemental analysis: Calculated: (%) C=41.4; % H=4.29; % S=6.5. Found:(%) C=41.8; % H=4.4; % S=6.74.

EXAMPLE 16

a) In a reaction vessel equipped with stirrer and thermometer, 8.75 g(50 mmol) of α,α,-dichloro-p-xylene and 18.6 g (150 mmol) of benzylmercaptan are stirred in 60 ml of toluene, until a clear solution isobtained. 200 mg of tetrabutylammonium hydrogen sulfate are partiallydissolved in 14 g of 50% aqueous sodium hydroxide solution, and themixture is added dropwise to the reaction mixture over a period of 10minutes at such a rate that the inside temperature does not exceed 45°C. 10 ml of toluene and 5 ml of water are added to the reaction mixture,which is then stirred at RT for 2 1/2 hours. The reaction mixture isdiluted with toluene, and the organic phase is extracted several timeswith water (pH˜7). It is dried with MgSO₄, the solvent is removed on arotary evaporator, and the residue is allowed to stand for 2 days. Thecrude product is dissolved in 100 ml of refluxing isopropanol, and themixture is allowed to cool to RT. The product is then allowed tocrystallize at 0°-5° C. for 3 hours. The suspension is filtered and theresidue is dried at RT overnight in a high vacuum. This gives 15.32 g(87.4% of theory) of p-xylylenedi(benzyl sulfide) of melting point64°-66° C.

Elemental analysis: Calculated: (%) C=75.38; % H=6.33; % S=18.29. Found:(%) C =74.9; % H=6.55; % S=18.35.

¹ H-NMR (100 MHz in CDCl₃) in ppm: 3.59 (multiplet, 8H); 7.25(multiplet, 14H).

b) A mixture of 1.75 g (5 mmol) of p-xylylenedi(benzyl sulfide) in 20 mlof methylene chloride is stirred in a 3-necked flask under nitrogen atRT, until a solution is obtained. 2.73 g (8.1 mmol) of triethyloxoniumhexafluoroantimonate are added to the mixture, which is then stirred for4 hours. Another 0.5 g (1.43 mmol) of triethyloxoniumhexafluoroantimonate is added, and the reaction mixture is stirredovernight. The reaction mixture is cooled to 0°-5° C. and filtered. Theresidue is stirred in 25 ml of water for 1 hour, the mixture isfiltered, and the crude product is dried at RT overnight in a highvacuum. The crude product is suspended in 90 ml of methanol and isheated in the refluxing solvent for 3-5 minutes. The suspension iscooled to RT, the product is allowed to crystallize at 0°-5° C. for 2hours, the suspension is filtered, and the residue is dried at RTovernight in a high vacuum. This gives 2.53 g (59.9% of theory) ofp-xylylenedi(benzylethylsulfonium)-di(hexafluoroantimonate) in the formof white crystals of melting point 157°-158° C.

¹ H-NMR (100 MHz, d₆ -acetone) in ppm: 1.45 (triplet, 2H); 3.55(quartet, 1H); 4.94 (singlet, 4H); 4.98 (singlet, 4H); 7.5-7.69(multiplet, 14H).

EXAMPLE 17

a) 3.51 g (10 mmol) of p-xylylenedi(benzyl sulfide) according to Example16a), 2.7 g (25 mmol) of benzyl alcohol and 4.88 g (30 mmol) of HBF₄(54% in diethyl ether) in 15 ml of methylene chloride and 50 ml of waterare reacted analogously to Example 9b) to give 4.37 g (61.7% of theory)of p-xylylenedi(dibenzylsulfonium) di(tetrafluoroborate) in the form ofwhite crystals of melting point 159°-161° C.

¹ H-NMR (100 MHz, d₆ -acetone) in ppm: 4.91 (singlet, 12H); 7.4(multiplet, 24H).

b) A mixture of 4.0 g (5.65 mmol) of p-xylylenedi(dibenzylsulfonium)di(tetrafluoroborate) is dissolved in 550 ml of acetone in a 3-neckedflask with slight warming. At room temperature, 4.38 g (16.94 mmol) ofsodium hexafluoroantimonate are added, and the mixture is stirred for 4hours. After the addition of 600 ml of methylene chloride, the reactionmixture is stirred at 0°-5° C. for 1 1/2 hours and filtered. The solventis removed from the filtrate on a rotary evaporator, and the residue isstirred in 50 ml of water at RT for 3 hours. The suspension is againfiltered, and the residue is dried at RT for 12 hours in a high vacuum.This gives 5.2 g (91% of theory) of p-xylylenedi(dibenzylsulfonium)di(hexafluoroanitmonate) in the form of colourless crystals of meltingpoint 130°-133° C.

¹ H-NMR (100 MHz, d₆ -acetone) in ppm: 4.95 (singlet, 12H); 7.40(multiplet, 24H).

WORKING EXAMPLES Example A

70 g of bisphenol A diglycidyl ether having an epoxide content of 5.25equivalents/kg, 30 g of 3',4'-epoxycyclohexylmethyl3,4-epoxycyclohexanecarboxylate having an epoxide content of 7.1equivalents/kg and 2 g of dibenzylethylsulfonium hexafluoroantimonateaccording to Example 1 are homogenized on a triple roll mill to give afine suspension. The gel time of this mixture is measured at 120° C. ona hot metal plate (gel time plate). The reactivity of the mixture andthe glass-transition temperature (T_(G)) are determined in adifferential scanning calorimeter (DSC), DSC TA 3000 instrument fromMettler AG, Greifensee, Switzerland, as follows.

1st run (50° to 300° C.; rate of heating 10° /min): measurement of thetemperature maximum of the enthalpy peak (peak temperature) and thereaction enthalpy (ΔH).

2nd run (50° to 250° C.; rate of heating 10° /min): measurement of T_(G)based on the enthalpy jump (average value). The measured results arelisted in Table 1.

Example B

A mixture is prepared as in Example A, using 2 g of tribenzylsulfoniumhexafluoroantimonate according to Example 2 as the sulfonium salt. Thegel time, peak temperature, ΔH and T_(G) are also determined in thismixture. The measured results are shown in Table 1.

Example C

1 g of dibenzylethylsulfonium hexafluoroantimonate according to Example1 is dissolved in 20 g of methylhexahydrophthalic anhydride to give aclear solution. This solution is mixed as in Example A with 70 g ofbisphenol A diglycidyl ether and 30 g of 3',4'-epoxycyclohexylmethyl3,4-epoxycyclohexanecarboxylate having an expoxide content of 7.1equivalents/kg to give a homogeneous liquid. Gel time, peak temperature,ΔH and T_(G) are also determined in this formulation. The measuredresults are shown in Table 1.

Example D

A mixture is prepared as in Example C, using 1 g of tribenzylsulfoniumhexafluoroantimonate according to Example 2 as the sulfonium salt. Geltime, peak temperature, ΔH and T_(G) are also determined in thismixture. The measured results are shown in Table 1.

Example E

A mixture is prepared as in Example C, using 1 g of tribenzylsulfoniumhexafluoroarsenate according to Example 3 as the sulfonium salt. Geltime, peak temperature, ΔH and T_(G) are also determined in thismixture. The measured results are shown in Table 1.

Example F

A homogeneous solution is prepared by heating 100 g of bisphenol Adiglycidyl ether according to Example A and 1 g of tribenzylsulfoniumhexafluoroantimonate according to Example 2 to about 50° C. Gel time,peak temperature, ΔH and T_(G) are also determined in this mixture. Themeasured results are shown in Table 1.

Example G

A homogeneous solution is prepared as in Example F by heating 100 g of3',4'-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate according toExample A and 1 g of tribenzylsulfonium hexafluoroantimonate accordingto Example 2 to 50° C. The measured results of this mixture with respectto gel time, peak temperature, ΔH and T_(G) are shown in Table 1.

Examples H-1 to H-14

According to Example C, 1 g of the sulfonium salt of Examples 4 to 17 isin each case dissolved in 20 g of methylhexahydrophthalic anhydride, ifnecessary with heating to <100° C., and mixed with 70 g of bisphenol Adiglycidyl ether and 30 g of 3',4'-epoxycyclohexylmethyl3,4-epoxycyclohexanecarboxylate to give a homogeneous liquid. Themeasured results of these mixtures are shown in Table 2.

                  TABLE 1                                                         ______________________________________                                        Measured results of the mixtures according to Examples A to D                 Mixture                                                                              Gel time Peak          Glass-tran-                                     accord-                                                                              at       temper-       sition tem-                                     ing to 120° C.                                                                         ature    ΔH                                                                           perature                                                                              Appearance                              Example                                                                              [sec]    [°C.]                                                                           [J/g]                                                                              T.sub.G [°C.]                                                                  of the resin                            ______________________________________                                        A      75       128      567  142     yellowish                               B      25       115      582  152     yellowish                               C      140      142      492  154     light yellow                            D      50       132      520  163     light yellow                            E      210      132      238   84     light yellow                            F      75       134      519  170     light yellow                            G      15       121      595  --*)    light yellow                            ______________________________________                                         *)no measurement                                                         

                  TABLE 2                                                         ______________________________________                                        Measured results of Examples H-1 to H-14                                             Sulfonium  Gel time at                                                                             Peak                                                     salt according                                                                           120° C.                                                                          temperature                                                                            ΔH                                                                           T.sub.G                             Example                                                                              to Example [sec]     [°C.]                                                                           [J/g]                                                                              [°C.]                        ______________________________________                                        H-1     4         110       128      471  154                                 H-2     5         40        127      524  155                                 H-3     6         17        113      511  155                                 H-4     7         50        131      520  156                                 H-5     8         30        128      514  158                                 H-6     9         65        130      507  154                                 H-7    10         22        122      509  152                                 H-8    11         <10        94      478  159                                 H-9    12         35        124      515  157                                  H-10  13         <10       106      512  160                                  H-11  14         95        137      493  156                                  H-12  15         130       138      507  159                                  H-13  16         140       142      516  154                                  H-14  17         60        124      513  154                                 ______________________________________                                    

Examples I-1 and I-2

According to Example C, 1 g of sulfonium salt is dissolved in each casein 20 g of methylhexahydrophthalic anhydride, if necessary with heatingto <100° C., and mixed with 50 g of bisphenol A diglycidyl ether and 50g of bisphenol F diglycidyl ether having an epoxide content of 6.1equivalents/kg to give a homogeneous liquid. The measured results areshown in Table 3.

                  TABLE 3                                                         ______________________________________                                        Measured results of Example I-1 and I-2                                       ______________________________________                                              Sulfonium Gel time Peak                                                       salt accord-                                                                            at       temper-          Appear-                             Exam- ing to    120°C.                                                                          ature  ΔH                                                                           T.sub.G                                                                            ance of                             ple   Example   [sec]    [°C.]                                                                         [J/g]                                                                              [°C.]                                                                       the resin                           ______________________________________                                        I-1   2         115      138    518  146  yellow-                                                                       brown                               I-2   4          50      130    514  151  yellow-                                                                       brown                               ______________________________________                                    

Examples K-1 to K-4

1 g of sulfonium salt is dissolved in each case in 10 g of a reactivesolvent and mixed with 50 g of bisphenol A diglycidyl ether and 50 g ofbisphenol F diglycidyl ether to give a homogeneous liquid. The measuredresults are shown in Table 4.

                  TABLE 4                                                         ______________________________________                                        Measured results K-1 to K-4                                                          Sulfo-               Gel   Peak                                               nium salt            time  tem-                                               accord-              at    pera-                                              ing to   Reactive    120° C.                                                                      ture ΔH                                                                           T.sub.G                           Example                                                                              Example  solvent     [sec] [°C.]                                                                       [J/g]                                                                              [°C.]                      ______________________________________                                        K-1    2        propylene   130   136  541   96                                               carbonate                                                     K-2    2        ε-Capro-                                                                          235   138  526  136                                               lactone                                                       K-3    2        γ-Butyro-                                                                           201   140  528  134                                               lactone                                                       K-4    4        Tetrahydro-  20   104  515  116                                               furfuryl                                                                      alcohol                                                       ______________________________________                                    

What is claimed is:
 1. A sulfonium salt of the formula I, II, III or IV##STR11## in which A is C₁ -C₁₂ alkyl, C₃ -C₈ cycloalkyl, C₄ -C₁₀cycloalkylalkyl, phenyl which is unsubstituted or mono- orpolysubstituted by C₁ -C₈ alkyl, C₁ -C₄ alkoxy, halogen, nitro, phenyl,phenoxy, alkoxycarbonyl having 1-4 C atoms in the alkoxy radical or acylhaving 1-12 C atoms, Ar, Ar¹ and Ar², independently of one another, areeach phenyl which is unsubstituted or mono- or polysubstituted by C₁ -C₈alkyl, C₁ -C₄ alkoxy, halogen, nitro, phenyl, phenoxy, alkoxycarbonylhaving 1-4 C atoms in the alkoxy radical or acyl having 1-12 C atoms oris naphthyl which is unsubstituted or mono- or polysubstituted by C₁ -C₈alkyl, C₁ -C₄ alkoxy, halogen, nitro, phenyl, phenoxy, alkoxycarbonylhaving 1-4 C atoms in the alkoxy radical or acyl having 1-12 C atoms,each arylene is phenylene which is unsubstituted or mono- orpolysubstituted by C₁ -C₈ alkyl, C₁ -C.sub. 4 alkoxy, halogen, nitro,phenyl, phenoxy, alkoxycarbonyl having 1-4 C atoms in the alkoxy radicalor acyl having 1-12 C atoms or naphthylene which is unsubstituted ormono- or polysubstituted by C₁ -C₈ alkyl, C₁ -C₄ alkoxy, halogen, nitro,phenyl, phenoxy, alkoxycarbonyl having 1-4 C atoms in the alkoxy radicalor acyl having 1-12 C atoms and Q.sup.⊖ is SbF₆ ⁻, AsF₆ ⁻ or SbF₅ OH⁻.2. A sulfonium salt of the formula I or II according to claim 1, inwhich A is C₁ -C₁₂ alkyl, C₃ -C₈ cycloalkyl, C₄ -C₁₀ cycloalkylalkyl,phenyl which is unsubstituted or mono- or polysubstituted by C₁ -C₈alkyl, C₁ -C₄ alkoxy, halogen, nitro, phenyl, phenoxy, alkoxycarbonylhaving 1-4 C atoms in the alkoxy radical or acyl having 1-12 C atoms,Ar, Ar¹ and Ar², independently of one another, are each phenyl which isunsubstituted or mono- or polysubstituted by C₁ -C₈ alkyl, C₁ -C₄alkoxy, halogen, nitro, phenyl, phenoxy, alkoxycarbonyl having 1-4 Catoms in the alkoxy radical or acyl having 1-12 C atoms, or is naphthylwhich is unsubstituted or mono- or polysubstituted by C₁ -C₈ alkyl, C₁-C₄ alkoxy, halogen, nitro, phenyl, phenoxy, alkoxycarbonyl having 1-4 Catoms in the alkoxy radical or acyl having 1-12 C atoms, and Q.sup.⊖ isSbF₆ ⁻, AsF₆ ⁻ or SbF₅ OH⁻.
 3. A sulfonium salt of the formula I or IIaccording to claim 1, in which A is C₁ -C₁₂ alkyl or phenyl which isunsubstituted or substituted by halogen or C₁ -C₄ alkyl, Ar, Ar¹ andAr², independently of one another, are each phenyl which isunsubstituted or mono- or polysubstituted by C₁ -C₈ alkyl, C₁ -C₄alkoxy, Cl or Br and Q.sup.⊖ is SbF₆ ⁻ or SbF₅ OH⁻.
 4. A sulfonium saltof the formula II according to claim 1, in which Ar, Ar¹ and Ar²,independently of one another, are each phenyl which is unsubstituted orsubstituted by C₁ -C₈ alkyl, C₁ -C₄ alkoxy, Cl or Br and Q.sup.⊖ is SbF₆⁻ or SbF₅ OH⁻.
 5. Tribenzylsulfonium hexafluoroantimonate,tris(p-methylbenzyl)sulfonium hexafluoroantimonate,tris(p-chlorobenzyl)sulfonium hexafluoroantimonate anddibenzylphenylsulfonium hexafluoroantimonate.